We have Waystones for rapid travel, but not all areas have them so I like riding Sampson to cut down travel time.
Can the MC take Sampson through the Waystones? It doesn't work for carts, and most riding horses mass around half a ton. How would combat be handled if the MC is attacked while mounted? Would Sampson be a separate combatant, or a modifier to the MC's stats? Would the MC have time to dismount? Is Sampson war-trained? (I doubt it, warhorses are notoriously difficult to work with.)
I do absolutely like the mental image.